“RDF Next Step” Workshop

hedgebornabaloneSoftware and s/w Development

Dec 2, 2013 (3 years and 8 months ago)

78 views

Ivan Herman

W3C

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Current RDF has been published in 2004


Significant deployment since then


implementation experiences


users’ experiences


Some cracks, missing functionalities, etc, came
to the fore


There are significant communities that have not
picked up RDF


e.g., Web Developers

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Shall we


live with those issues and go on with our lives?


dump it and start all over again from scratch?


do some minimal changes?

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W3C organized a Workshop in June 2010


32 submissions, 28 accepted, 18 were presented at
the workshop


2 busy days at Stanford (courtesy of NCBO)

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5

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Try to answer the question: live with it, redo it,
mend it…


if something has to be changed, what is it and with
what priority?


Give a list of possible work items, with priorities

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Yes, it is probably o.k. to touch
some
issues


But we have to be
very

careful not to send the
wrong signal to adopters, tool providers, etc.


I.e.:
keep the changes to the minimum


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Workshop report published:


http://www.w3.org/2009/12/rdf
-
ws/Report.html


W3C Team began working on chartering


…but felt the larger community should be asked


A questionnaire was published in August 2010


http://www.w3.org/2002/09/wbs/1/rdf
-
2010/results


And, of course, lots of discussion on various
fora


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I will list the major items that came up during
the discussions


mostly the
Workshop+Questionnaire
, plus some
others


I will list them in the order of


may end up in the RDF Working Group Charter


should be done but not clear yet where and how


postpone it for now

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There are some errata that have to be taken
care of


exact relationship to IRI
-
s


more flexible references to XML versions


etc


Not worth discussing them here

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A.k.a. “named graphs”, “quoted graphs”,
“knowledge bases”


Is on the top of all priority lists…


But the semantics is not absolutely clear


e.g., are we talking about a mutable or immutable
collection of triples?


maybe we have two different concepts here…

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We have a stable “team submission”, widely
used by the community


another top priority item…


Additional syntax should be added for graph
identification

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Is essential for Web Developers


The syntax may not be a complete syntax; to be
decided as we go


e.g., no blank nodes, only syntax for
Skolemized

nodes


The syntax may also include tools for lists,
graph identification, etc.


Note that it may make sense to separate that
into a different group…

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Some features may be deprecated: reification,
containers, …


Unclear what “deprecation” means in this
context


old RDF graphs should not become invalid…

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A number of semantics extensions and features
have appeared in Recommendations since


rdf:plainLiteral


“finite” versions of RDF(S) semantics as part of the
SPARQL 1.1 entailment regimes


bridge between URI
-
s

as strings and RDF resources in
POWDER


Probably useful to reconcile these in one place
for wider and easier adoption

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oData
, for example, is gaining ground:


“…Web protocol for querying and updating data that
provides a way to unlock your data and free it from
silos that exist in applications today”


Relationship between RDF and these should be
defined


oData
/Atom based serialization of RDF?

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General guidelines for
bnode

Skolemization


e.g., define a scheme of the form


http://bnode.w3.org/{uuid}


… that could be used by some syntaxes,
ie
, consumers
would know that this is, in fact, an anonymous node


There are a number of Recommendation that
rely on
Skolemization

(e.g., SPARQL)

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We currently have plain literal,
xsd:string
,
rdf:plainLiteral



it leads to, e.g., convoluted SPARQL queries


These should be harmonized

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Refresh the vocabulary examples being used


Multi
-
syntax example (like, e.g., the OWL
documents)


Linked Data guidelines should be included


“follow your nose”


usage of
owl:sameAs

or others


etc.

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Issues that arose:


httpRange
-
14 as a standard


“Cool URI
-
s

for the Semantic Web”


“follow your nose principles”


social contracts around URI
-
s


etc.


Not clear that these should be
Recommendations


Some of the issues might become part of a
renewed RDF Primer


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Clearly a major problem to be solved


There is a general requirement (graph
identification) that is part of the RDF Core


W3C may start a separate group on Provenance
vocabularies

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Goal: define a subset of (essentially) OWL 2 RL


more palatable to developers


can be “referenced” as an entity, not only a set of rules


Should be done, not clear where and how


not clear this should be part of an RDF Core


would a SWIG Note be enough, or does it need a full
Recommendation status?



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Mainly on the Linked Data Cloud
owl:sameAs

is
widely used


the usage is not necessarily semantically correct


a vocabulary should be defined to reflect the various
usages



could be very close to the relevant SKOS terms, actually…


Some elements may be part of an updated RDF
Primer

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A bit like
RDFa

1.1’s profile mechanism


a single file that collects all namespaces in one


May find its way as part of the JSON serialization


not explicitly out of scope, but has not been added as
a requirement either

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Mainly the Web Developers’ community needs
API
-
s


But there is already an established set of API
-
s

in Java, Python, etc


The
RDFa

API work defines its own API which
includes a more generic RDF API mainly for
Javascript


Not clear whether a separate group would be
necessary…

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RDF/XML is generally disliked


no one wants to spend time on improving it…


New features (e.g., graph identification) may not
find its way to RDF/XML

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There is a disconnect between the formal,
model
-
theoretic semantics of RDF(S) and
applications


there are also theoretical inadequacies, too


But the overall feedback was: don’t touch it,
deployment has learned to live with it, etc.


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Bnodes

as predicates, literals as subject


Literals as subject has deeply divided the
community


some are violently against it, others ask for it


clearly no consensus at the moment!

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W3C team should finalize the charter soon


Then the W3C process kicks in


AC members vote with a yea or nay


if the vote is positive: work can begin in early 2010